I have a house in Greyton and have spent some time in the area. Although there are a lot of great hikes there don't seem to be nice boulder fields. The kloof mentioned by Justin is very Narrow and pretty and you would have to do some wading at the beginning to get up into it proper. I wanted to scope it out for climbing as it looked like it had some potential. But it was winter with snow on the mountains and the water was absolutely freezing so I did not push through.

It would definitely be worth looking at from a climbing perspective... let me know if you venture up there

I didn't find any good bouldering fields but did go all the way up the kloof and swam across the two pools which block its northern end. Very beautiful place and definitely worth more exploring. I'm a rank novice at climbing and have no skill at assessing climbing potential. That said, the sides of the kloof and some crags above it at the entrance looked quite interesting. There's a spot on the left going up with an impressive arched overhang.